JWSS - Journal of Water and Soil Science

---

This experiment was conducted to estimate genetic parameters of some of the important traits of silkworm in two populations, namely, Japanese and Chinese lines in Iranian Silkworm Rearing Co-Natanz. Based on single pair mating method, 9 male moths mated with 9 female moths and then raised under standard environmental conditions. Performance of 30 progenies of each pair was recorded.

Heritability coefficients (parental full-sib method) of single cocoon weight (CW), shell weight (SW), pupal weight (PW) and shell ratio (SR) were estimated to be 0.209±0.123, 0.228±0.129, 0.174±0.109 and 0.044±0.042 in the Japanese race and 0.196±0.1l8, 0.234±0.132, 0.159±0.103 and 0.00, in the Chinese race, respectively. Genetic and phenotypic correlation between CW & SW were 0.645 & 0.957, CW & PW, 0.962 & 0.982, CW & SR -0.351 & 0.123, SW & PW, 0.496 & 0.871, SW & SR, 0.265 & 0.457, PW & SR, -0.446 & 0.169, respectively. Selection, based on heritability coefficients of single cocoon weight and shell weight, can be applied successfully to genetic-gain in this trait. Based on correlation coefficients between traits, selection for shell weight can be applied successfully to improve other traits such as single cocoon weight and shell ratio.

---

The effect of mulberry leaves enrichment with riboflavin in 7, 37, 77 and 127ppm concentrations on larval growth and cocoon characteristics of Bombyx mori L., hybrid 103×104 was studied. Silkworm larvae were fed on fresh mulberry leaves of shin inche nevise enriched with riboflavin once a day. All biological and economical parameters were determined by using standard techniques in sericulture. The results showed that larval weight was greater in 77ppm among treatments on the 7th day of the fifth instar which had 47% increase compared to control. Maximum amount of female cocoon weight and female pupal weight were recorded 1.622g and 1.169g, respectively, in 127ppm while male cocoon weight and pupal weight were greater in 37ppm and recorded to be 1.169g and 0.895g, respectively. Maximum amount of cocoon shell weight and cocoon shell ratio were recorded in 77ppm for male (0.311g and 26.06%) and female (0.318g and 21.46%). Maximum weight of 50 eggs (0.027g) was recorded in 127ppm while high fertility and hatchability was recorded in 77ppm concentration. Effective rate of rearing was maximum in control treatment (72%) with no significant difference compared with other treatments. The overall results showed that riboflavin can be used at 77ppm concentration for the significant increase of cocoon weight, cocoon shell ratio and egg production of silkworm, Bombyx mori L.